The Auto Mechanic (Diesel) Passbook® prepares you for your test by allowing you to take practice exams in the subjects you need to study. It provides hundreds of questions and answers in the areas that will likely be covered on your upcoming exam, including but not limited to: operating principles of internal combustion automotive components such as engines, transmissions, clutches, brakes, wheels, tires; troubleshooting and repair of motor vehicle components, accessories and systems; tools, equipment and safety; electrical and electronic principles and systems; automotive inspections and emissions testing; and more.